The present invention relates to electro-mechanical connection between two printed circuit boards, between a cable and a printed circuit board, and between an integrated circuit and a printed circuit board.
Typically, when solderless electro-mechanical connection between two printed circuit boards is sought, "daughter" circuit boards are electro-mechanically connected to a "mother" board as shown in FIG. 1. In FIG. 1 a daughter board 9 includes a series of electrically conductive fingers 8 on a cut out section 7 of daughter board 9. Section 7 with fingers 8 are inserted into an edge connector 15 which is attached to a mother board 10.
In FIG. 2A, a cross-section of edge connector 15 is shown. Contacts 13 and 14 of edge connector 15 are shown soldered to mother board 10 at joints 11 and 12 respectively. Contacts 13 and 14, are configured for surface mount connection onto mother board 10. Contacts 13 and 14 form one of many pairs of contacts in edge connectors 15. All the pairs of contacts of edge connector 15 are covered by a shell 17, typically made of high temperature plastic. Fingers 16 on from fingers 8 are shown ready to be inserted between contacts 13 and 14.
In FIG. 2B, section 7 with fingers 8 of daughter board 9 have been inserted into edge connector 15. Contacts 13 and 14 are shown to have been bent to make room for the insertion of section 7 and fingers 16. The spring action of contacts 13 and 14 provide electro-mechanical contact between contacts 13 and 14 and fingers 16.
In FIG. 2C, instead of a surface mount connection, contacts 13 and 14 have been placed through circuit board 10 and soldered at points 18 and 19.
An alternate prior art embodiment of edge connector 15 is shown in FIG. 3. A single contact 33 is bent as shown and soldered to mother board 10 at joints 31 and 32. When section 7 with fingers 8 of daughter board 9 is inserted into edge connector 15, contact 33 expands to receive section 7 and fingers 16, as shown in FIG. 4. The spring force of contact 33 attempting to contract to its original position establishes electro-mechanical connection between contact 33 and fingers 16.
The prior art connectors shown have a number of drawbacks. For instance, the spring action used to hold section 7 and fingers 8 to edge connector 15, may provide an unreliable mechanical bond. Further the soldering required in each of the prior art embodiments, which use surface mount technology, lessens the reliability of the connection because of thermal expansion and contraction which takes place during soldering and usage. Also, mechanical installation may weaken and/or fracture the solder bonds.